Furnace



no. FURNACES,

,l "fa-mace structuren 2 Sheets-Sheet 2.

. POWELL.

PURNAGE.

U. wir? f Patented Deo. 17, 1.895.

*v UNITED STATES PATENT EEICE.

EDVIN POIVELL, OF PITTSBURG, PENNSYLVANIA.

FuRNAoE.

SPECIFICATION forming part of Letters Patent No. 551,476, dated December17, 1895.

Application filed August 28, 1895. Serial Nm 560,747. (No model.)

To aZZ whom it may concern:

Be it known that I, EDWIN POWELL, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented or discovered a certain new and usefulImprovement in Furnaces, of which improvement the following is aspecification.

My invention relates to furnaces for the evolution of heat from fuel inthe various descriptions of heating apparatus employed in manufacturingand mechanical operations and the generation of steam for the numerouspurposes required in the arts and trades; and its object is to providemeans whereby the thorough, economical, and smokeless consumption offuel may be effected in a structure of simple and inexpensiveconstruction and ready applicability to existing conditions of location,service, and relation to other structures in connection with which itmay be required to be used.

To this end my invention, generally stated, consists in the combinationof a furnace or fuel-chamber, a fire-bed therein which is closed toaccess of air below it, an air-supply passage above said fire-bed, acombustionchamber, an exit throat or passage connecting thefuel-chamber, at or near the fire-bed thereof, with thecombustion-chamber, and a gas-conduit leading from the fuel-chamber,above the normal plane of ineandescence therein, to a point of dischargeadjacent to the discharge-outlet of the exit throat or passage.

The improvement claimed is hereinafter fully set forth. 1

In the accompanying drawings, Figure 1 is a vertical longitudinalcentral section through a metallurgical furnace, illustrating anapplication of my invention; Fig. 2, a vertical transverse sectionthrough the same at the line w of Fig. 1;A Fig. 3, a verticallongitudinal central section through a glass-furnace, illustrating amodification of detail;` and Fig. 4, a vertical' transverse sectionthrough the same at the line y y of Fig.v 3.

In the practice of my invention I provide a downward-draft furnace orfuel-chamber 1, having at or near its top a fuel-supply passagepropenjmg 2, closed by a door 3, and having its bottom formed by a gratedor perforated iire-bed 4, the openings in which are provided to permitthe passage of ashes into a lower closed ash-pit 5, having a tight door6 for the removal of ashes, and provided preferably with a water-pan Gon its bottom. The walls of the fuel-chamber 1 are closed on all sides,except as to the openings of the fuelsupply passage 2 and fire-bed 4,above specified, one or more air-supply passages 7 formed in the frontwall of the fuel-chamber at a point above the normal level of the fueltherein and controlled by a door or register 8, a cleaning-passage S) inthe front wall at or near the level of the fire-bed, controlled bya door10, and gas-discharge passages 11 and 12, to be presently described. Theash-pit being also tightly closed, the draft of the fuel-chamber isdownward from the air-supply passages 7 through thenbody of fuel.

A combustion-chamber 13, in which the heat evolved from the fuel in thefuel-chamber 1 is utilized for the particular purpose for which it mayberequired-as, for example, the melting or reheating of metal, glass,rizo., the burning of brick, lime, or pottery, the generation=of steam,or other calorific action-is located adjacent to the fuel-chamber l, andis separated therefrom by the rear wall 111 thereof. An exit throat orpassage 11, through which the major portion of the gaseous products ofcombustion evolved from the fuel in the fuel-chamber 1 are dischargedinto the combustion-chamber 13, leads from the fuelchamber l, at orabout the level of the highest incandescence therein-that is to say, ator closely adjacent to the top of the fire-bed 4--into thecombustion-chamber 13. A gasconduit 12, of which either one or more maybe employed, a plurality being indicated in dotted lines in Fig. "2,leads from the fuelchamber 1 at a point above the normal plane ofincandescence therein, and, preferably, as shown, slightly above the topof the normal charge of fuel in the chamber, to a point of discharge tothe combustion-chamber adjacent to the discharge-outlet of the exitthroat or passage 11 thereto, the object of said conduit 12 being toprovide an avenue for the passage of the smoke and partially-consumedgases which may rise through the unconsumed and cooler portions of thefuel, at and below the top of the charge, from the upper poortion ICO -1o tion of portions of the-charge above that which is in a state ofincandescence is found to be completely consumed.

As shown in Fig. 1, the point of discharge of the gas-conduit 12 is onone of the b0unda ries of the exit throat or passage 11, between thefire-bed 4 and the outlet ofthe passage 11, to the combustion-chamber13, so that the products of combustion which pass through the conduit 12meet the heated gases passing zo through the exit-throat 1l before thelatter are discharged into the combustion-chamber,

, and the conduit 12 and passage 11 thus have a common outlet to saidchamber, which outlet is adjacent to the point of dischargeof theconduit 12. The same result willfhowever, be attained if the conduit 12and passage 11 deliver the gaseous products from the fuelchamber to thecombustion chamber through separate and contiguous outlets, the

3o only requisites as to the location of the point of discharge of theconduit 12 being that it shall be such that the gaseous products pass-4ing out of the conduit 12 must immediately mingle with the hot gaseswhich pass through 3 5 ,the exit throat orfpassagel, and that it shallbe sufhciently far remove from the fire-bed to insure that the gaseousproducts passing through the conduit 12 shall escape therefrom entirelybeyond and clear of all portions 4o of solid fuel, and shall meet thegases which are evolved from the incandescent portion of the fuel at apoint where their traverse is unimpeded by solid fuel or ashes.

Figs. 3 and 4 illustrate a modification in which the discharge of theproducts of combustion from the exit throat or passage 1l and thegas-conduit 12, respectively, is effected through separate outlets, asabove specified, the outlet of the passage 1l opening into thecombustion-chamber 13, as in the instance first described, and that ofthe gas-conduit 12,

also opening into the combustion-chamber,

above and closely adjacent to that of the passage 11. Thepartially-consumed products of combustion escaping from the outlet ofthe gas-conduit 12 meet and mingle with the n' T-heated gases dischargedfrom the outlet of the assage 11, as both enter the comvbustion-chamber, and the former are, as in the instance first described,thoroughly consumed, producing a iame of intense heat in thecombustion-chamber. The combustionchamber 13 is shown as of the formemployed in glass-furnaces, having glory-holes 15 in the upper portionofl its walls, but it will be obvious that it may be of any otherdesired construction, without departure from my invention.

l have found in practice that an unusually high heat is generated, and acomplete com- 7o bustion effected, by a construction embodying theessential features above described, and, while the precise action of thefurnace in the evolution and combustion of gasesmay be difficult ofascertainment with absolute certainty, it is my present understandingthat this advantageous result is due to the following facts: The smokeand partially-consumed gases which are vevolved from the portion of thebody of fuel above that which is in a high 8o statel of incandescenceare disengaged and pass ou slowly, -at a comparatively low tem.-perature, owing to the resistance of the unconsumed and cold solid fuelabove the level at which they are generated. On the other hand, thegases evolved from the incandescent portion of the fuel escape freely,rapidly, and at a high-temperature through the exit-passage 11. Thelatter gases are, therefore, capable of carrying with them and con- 9osuming and utilizing the combustible products which meet and mingle withthem at the ldischarge-outlet of the conduit l2, thereby generating acorrespondingly higher degree -of heat than would be attainable if theunconsumed products from the upper portion l. of the charge of fuel wereled into and through the incandescent portion thereof, and before thegases of combustion were released therefrom, as has been proposed, andset forth in roo Letters Patent, prior to my present invention.

The essential feature of difference between my improvement and the priorconstructions referred to consists in the provision of the describedmeans for eecting the union of the productsof combustion of adownwarddraft furnace from the unconsumed and the incandescent portionsof the charge of fuel, respectively, at a point wholly exterior to thefuel-chamber, where the traverse of the hot 1 1o ter gases is unimpededby solid fuel, and so that combustion shall s .1 i a t the outletthrough which the gaseous products pass into the combustion-chamber, andproduce a flame of exceptionally high heatat said outlet.

I claim as my invention and desire to secure by Letters Patent- 1. Thecombination, substantially as set forth, of a furnace or fuel chamber, arebed 12o therein which is' closed to access of air from below it, anair supply passage above said rebed', a combustion chamber, an exitthroat or passage connecting the fuel chamber, at or near its rebed,with the combustion cham- '125 ber, and a gas conduit leading from thefuel chamber, above the normal plane of incan' descence therein, to apoint of discharge adjacent to the discharge outlet of the exit Y throator passage and exterior to the bed 0f r 3o incandescent fuel.

2. The combination, substantially as set F-J-rnace structured forth, ofa furnace or fuel chamber, a rebed therein which is closed to access ofair from below it, an air supply passage above said irebed, a combustionchamber, and passages connecting the fuel chamber and combustionchamber, said passages leading out of the fuel chamber at or near thepoint or level of highest incandescence, and above the normal plane ofincandescence, respectively, and discharging exterior to the bed ofincandescent fuel.

3. The combination, substantially as set forth, of a furnace or fuelchamber, a rebed therein which is closed to access of air from below it,an air supply passage leading into the fuel chamber above the normalupper level of the charge of fuel, a door or register controlling saidpassage, a combustion chamber, an exit throat or passage leading fromthe fuel chamber, at or near the level of the rebed, to the combustionchamber, and a gas conduit leading from the fuel chamber, above thenormal upper level of the charge of fuel, and discharging, exterior tothe bed of fuel, to the combustion chamber.

4. The combination, substantially as set forth, of a furnace or fuelchamber, a irebed therein which is closed to access of air from belowit, an air supply passage above said and having its discharge outletWholly exterior to the fuel chamber and open to the products ofcombustion delivered through the exit throat or passage.

5. The combination, substantially as set forth, ofa furnace or fuelchamber, a flrebed therein which is closed to access of air from belowit, an air supply passage above said irebed, a combustion chamber, anexit throat or passage leading from the fuel chamber, at or near itsiirebed, to the combustion chamber, and a gas conduit leading from thefuel chamber, above the normal plane of incandescence therein, to thecombustion chamber, and having a discharge outlet therein, independentof, land adjacent to, that of the exit throat 0r passage.

In testimony whereof I have hereunto set my hand.

EDWIN POWELL.

Witnesses GEO. W. BLAIR,

.T. SNOWDEN BELL.

